Default extrusion algorithm.

The algorithm uses constant section parts cut at spine points in a way similar to what a framer would do to build a frame. This provides a better continuity of the shape and avoids cracks.

This algorithm determines the piecewise extrusion directions as a vector between consecutive spine points. This means that zero or really small distances between consecutive points can produce odd extrusion directions and result in wrong geometry. It is up to the application to filter spine points to avoid these cases. The algorithm can produce odd geometries when spines points are overlapping or zigzags.

Old extrusion algorithm.

It does not guarantee that extrusion portions have constant section and shapes could be more twisted.

Smooth but avoids self intersections caused by large curvature radius of the spine.

When the spine has curves with a large curvature radius compared to the radius of the extrusion section, SMOOTH generation might produce self intersections. Use this mode to avoid self intersections at the cost of some localized violation of the extrusion smoothness. (Section parts at spine joints may not be constant where self intersections were present.) This mode is useful to avoid artifacts in boolean results when OIV.Inventor.Nodes.SoBaseExtrusion derived objects are used as operands for CSG operations.